KLM's ????????-hour rule permits travellers to make changes to their bookings or cancel their flights by phone at ❝+ +1 "844[488]0875 (USA) & +1 "844[488]0875 (UK) ) or +1 "844[488]0875 (USA) & +1"844[488]0875 (UK) (USA) https://www.devex.com/people/what-is-the-24-hour-rule-for-klm-2386356